Discussion
Diagnosis With Brief Discussion
- Diagnosis
- Sarcoidosis
- Radiologic Findings
- HRCT scans show multifocal patchy pulmonary nodules, centrilobular and subpleural micronodules, bronchovascular bundle thickening, and diffuse and nodular thickening of the interlobar fissures (perilymphatic distribution).
- Brief Review
- Sarcoidosis is a multisystem disorder of unknown cause.
It most commonly affects young and middle-aged adults (20 - 40 years) and frequently presents with bilateral hilar lymphadenopathy, pulmonary infiltration, and ocular and skin lesions (1).
Fifty percent of patients are asymptomatic, 25% presented with respiratory symptoms and the remaining 25% had extrathoracic symptoms.
Pulmonary function test produces restrictive impairment with reduction in lung volume.
The plain radiographic changes of thoracic sarcoidosis are classified for descriptive purpose into four groups.
Stage 0 : No demonstrable abnormality
Stage 1 : Hilar and mediastinal lymph node enlargement unassociated with pulmonary abnormality
Stage 2 : Hilar and mediastinal lymph node enlargement associated with pulmonary abnormality
Stage 3 : Diffuse pulmonary disease unassociated with node enlargement
The combination of symmetric bilateral hilar and right paratracheal lymph node enlargement ("1-2-3" sign) is characteristic. Other common site of lymphadenopathy include aortopulmonary window and subcarinal region (2).
Nodal calcification is a late manifestation.
Nodular thickening of the bronchoarterial interstitium involving mainly the middle and upper lung zone is characteristic feature. Nodules are also seen along the interlobular septa and centrilobular structures. Miliary nodules are uncommon findings. Bilateral, symmetric air-space consolidation involving mainly mid- and upper lung zones can be seen. Ground-glass opacity is present on HRCT and related to the interstitial granuloma or micrscopic foci of fibrosis.
About 20 % develop pulmonary fibrosis. On HRCT, the fibrosis has a characteristic peribronchovascular distribution radiating from the hila to upper lobe. Architectural distortion, traction bronchiectasis, and honeycombing are irreversible abnormalities in pulmonary fibrosis.
Diagnosis is obtained in the majority of patients by transbronchial lung biopsy.
- References
- 1. Nagai S. Pulmonary sarcoidosis : pathogenesis and population difference. Intern Med 1995;34:833
2. Sider L, Horton ES Jr. Hialr and mediastinal adenopathy in sarcoidosis as detected by computed tomography. J Thorac Imag 1990;5:77
- Keywords
- Lung, Mediastinum, Non-infectious inflammation, Sarcoidosis,